BCC for Privacy!

BCC stands for "Blind Carbon Copy."
Historically, it would indicate who had received (or should receive) a
copy of a memo without being listed in the "To" or "CC" fields.
In the context of email, it indicates who should receive a copy of the
email without being listed in the headers.
If you're sending email to a number of people who do not (or should
not) know each other, it is courteous to conceal their email addresses
by using BCC.

Many people are protective of their email addresses.
They don't care to receive email from random people on the net.
Perhaps you've decided your clever joke, worthy cause, or business
announcement was worth sending to them.
You've also sent their email address to everyone else on the mailing.

Look at it another way, would you send your entire holiday card list
out with each card you sent? Of course, some people would not like
getting the list and others would not appreciate being on the list
being sent everyone.

And if you're in business, would you think of giving away your contact
list?
That's what you're doing by including everyone in the To or CC fields.
And some recipients of your mailing might consider everyone else on
your list interested in similar mailings and feel free to use the list
themselves.

Viruses and spam-bots are now designed to go through mail files and
address books looking for potential addresses.
Sending a single message individually addressed to a large list of
people increases the chances that they all will be spammed or sent a
virus should any one of them get infected.

Out of respect for your recipients, would you please consider
not
listing them each individually in your mailings?

If your "mailing list" is personal, you can just use BCC for all the
names.
(You can send it To yourself.)
If it's a more business oriented list, why not make it an official
mailing list at your site and use the alias rather than including
everyone's name and email address in the headers?
You can set up free mailing lists at
Google Groups
or
Yahoo! Groups.
To protect your list from abuse, you still may wish to BCC it.

Interestingly,
not
using BCC when sending email to a large group who don't know each
other appears to be against Google's
Gmail's program policies.
They list as one of the prohibited actions,
"selling, exchanging or
distributing to a third party the email
addresses of any person without such person's knowing and continued
consent
to such disclosure."
(emphasis added)

'You've Got Mail,' More and More, and Mostly, It Is Junk
(A NY Times article -- free, but registration required - which
describes the growing problem of junk email: "To shield
themselves from junk e-mail, many Internet users have become
increasingly wary of divulging their addresses."
)